by Charisse Jones, USA TODAY

by Charisse Jones, USA TODAY

NEW YORK -- Delta Air Lines said Tuesday that it will buy a significant stake in Virgin Atlantic, a move that will give it a stronger foothold at London's Heathrow Airport, one of the most important business portals in the world.

Delta said it would buy 49% of Virgin Atlantic for $360 million and seek to form a joint venture that would allow the two carriers to share revenue.The agreement needs antitrust approval by regulators in the U.S. and Europe.

The deal would give Delta greater appeal to premium-paying passengers doing business across the Atlantic.

"There's no question the whole focus of this deal ... was helping Delta get more access to London,'' said travel analyst Henry Harteveldt. "It's the most important international business market outside North America. The New York-to-London route in particular is critical to meet the needs of corporate travelers, and among them especially the people who pay for the business-class tickets, which is where Delta and other airlines earn a majority of profits.''

Vicki Bryan, senior high yield analyst at GimmeCredit, a corporate bond research service, said in a note to investors that the deal is a smart move.

"Delta gains greatly expanded access to Heathrow Airport and Virgin's elite passengers, ideal target customers and Virgin gets a potentially life saving shot in the arm with Delta now as a partner,'' she wrote.

Takeoff and landing slots at Heathrow Airport are limited, and among U.S. carriers, American Airlines has been able to dominate traffic from New York to London through its membership in the Oneworld Alliance, which includes British Airways. Virgin Atlantic flies the second largest number of passengers at Heathrow.

Owning a stake in Virgin Atlantic brings Delta "a lot closer to American as a competitor between the U.S. and London,'' particularly on the route between New York City and Heathrow, Harteveldt said.

Delta and Virgin Atlantic say the deal will result in 31 flights between Britain and North America for the two airlines on peak days, and a combined nine flights a day taking off from New York's JFK and Newark Liberty airports. .

Currently, Delta lags American and United in the number of flights between New York airports and Heathrow.

Delta said its goal is to have the joint venture in place by the end of next year.

Business mogul Richard Branson founded Virgin Atlantic in 1984, and 51% of the airline will remain in the hands of Branson's Virgin Group. The 49% stake being bought by Delta previously belonged to Singapore Airlines, which made its purchase in 1999.

The joint venture doesn't affect Virgin America, which flies inside the U.S.

Virgin Atlantic has struggled with losses and said in 2010 that it could be interested in some kind of tie-up with another airline.

If the joint venture is approved by regulators, Delta and Virgin Atlantic would continue to be independent airlines but would have a partnership that allows them to share costs and revenue. Passengers will be able to connect with greater ease between the airlines' networks, and use their frequent flier points on either carrier.

"We actually believe that this is incredibly pro-consumer, because now you're going to have a real competition in the marketplace, and competition makes our companies better,'' Delta CEO Richard Anderson said at a news conference Tuesday. Shares of Atlanta-based Delta Air Lines (DAL) rose almost 6.8% to $10.83 Tuesday.

Delta, in the last five to seven years, has put more emphasis on international flying. It's helping pay the $1.2 billion tab to renovate an international terminal at New York's JFK that will be home to both Delta and Virgin Atlantic.

It moved into Asia after merging with Northwest in 2008, and it's switched wide-bodied jets from domestic routes to international routes in Europe, Latin America and Africa. Currently, about 43% of Delta's flights are international, vs. 23% in 2005.

Across the Atlantic, there's a longstanding rivalry between Virgin and British Airways for passengers. Branson, for instance, for years fought regulatory approval of the alliance between British Airways and American that allows them to jointly book passengers.

Also indicative of the rivalry is an exchange between the two Monday, when Virgin announced it was challenging British Airways on its home turf by starting 24 new domestic flights between Heathrow and Scotland.

"Throughout our history, Virgin Atlantic has successfully fought British Airways all over the world and has offered passengers a compelling alternative through our renowned product and service," Virgin Atlantic CEO Steve Ridgway said announcing the new routes. "We will look to replicate that in our short-haul program and challenge the current BA monopoly on these routes, which is causing serious consumer harm."

Virgin Atlantic is teaming with Aer Lingus to run the flights. Aer Lingus will provide the crew and Airbus narrow-body aircraft required. But the planes will be branded as Virgin.

British Airways Chief Executive Willie Walsh told London's Daily Telegraph newspaper that Delta was mainly interested in Virgin Atlantic so it can get slots at Heathrow, and that it would not want to keep the Virgin brand.

But Delta's Anderson, at the news conference Tuesday, strongly disagreed.

"The whole purpose is to join the networks and join the brands together,.'' he said.